The present invention relates to an automated storage/retrieval system, more specifically to an automated storage/retrieval system having at least two pairs of multi-tier racks.
Japanese Examined Patent Application Publication No. HEI5-21802 discloses an example of a conventional automated storage/retrieval system. This automated storage/retrieval system 1 includes at least one pair of left and right multi-tier racks 3L, 3R, each having multi-tier shelves 2. At each tier between the multi-tier racks 3L, 3R is provided a transferring shuttle 4 that can run in a horizontal direction. Moving a load P upward and downward is performed by an elevator 6 that is disposed at one end of the multi-tier racks 3L, 3R and has two elevating platforms 5L, 5R. Further, delivering a load P to and receiving a load P from the elevating platforms 5R, 5L of the elevator 6 is performed by one storage conveyor 7 and one retrieval conveyor 8.
In such an automated storage/retrieval system 1 having a conventional configuration, in order to improve throughput performance and storage capacity, pairs (only two pairs are illustrated in FIG. 9) of the multi-tier racks 3L, 3R may be arranged right and left, and accordingly the number of the elevator 6, storage conveyor 7 and retrieval conveyor 8 may be added, as illustrated in FIG. 9.
However, to arrange the multi-tier racks 3L, 3R in parallel, the number of equipment composing the automated storage/retrieval system 1 is simply scaled, increasing a facility cost and requiring an excess space for installing the automated storage/retrieval system 1.
The number of tiers of the multi-tier racks 3L, 3R may be increased in order to increase storage capacity, but if a building for a system has a height limit, the number of tiers cannot be simply increased. In addition, the increase of the number of tiers of the multi-tier racks 3L, 3R increases storage capacity, but extends the lifting stroke of elevator 6, which in turn takes more time for elevator movement, thus decreasing throughput performance.